INNOCENT X. (Giovanni Battista Pamfili) was born in Rome on the 6th of May 1574, served successively as auditor of the Rota, nuncio to Naples, legate apostolic to Spain, was made cardinal in 1627, and succeeded Urban VIII. as pope on the 15th of September 1644. Throughout his pontificate Innocent was completely dominated by his sister-in-law, Donna Olimpia Maidalchini, a woman of masculine spirit. There is no reason to credit the scandalous reports of an illicit attachment. Nevertheless, the influence of Donna Olimpia was baneful; and she made herself thoroughly detested for her inordinate ambition and rapacity. Urban VIII. had been French in his sympathies; but the papacy now shifted to the side of the Habsburgs, and there remained for nearly fifty years. Evidences of the change were numerous: Innocent promoted pro-Spanish cardinals; attacked the Barberini, proteges of Mazarin, and sequestered their possessions; aided in quieting an insurrection in Naples, fomented by the duke of Guise; and refused to recognize the independence of Portugal, then at war with Spain. As a reward he obtained from Spain and Naples the recognition of ecclesiastical immunity. In 1649 Castro, which Urban VIII. had failed to take, was wrested from the Farnese and annexed to the Papal States. The most worthy efforts of Innocent were directed to the reform of monastic discipline (1652). His condemnation of Jansenism (16J3) was met with the denial of papal infallibility in matters of fact, and the controversy entered upon a new phase (see JANSENISM). Although the pontificate of Innocent witnessed the conversion of many Protestant princes, the most notable being Queen Christina of Sweden, the papacy had nevertheless suffered a perceptible decline in prestige; it counted for little in the negotiations at Munster, and its solemn protest against the peace of Westphalia was entirely ignored.
Innocent died on the 7th of January 1655, and was succeeded by Alexander VII.
For contemporary lives of Innocent see Oldoin, continuator of Ciaconius, Vitae et res gestae summorum Pontiff. Rom. ; and Palazzi, Gesta Pontiff. Rom. (Venice, 1687–1688) iv. 57o sqq. ; Ciampi's Innoc. X. Pamfili, et la sua Corte (Rome, 1878), gives a very full account of the period. Gualdus' (pseud. of Gregorio Leti; v. bibliog. note, art. " SIXTUS V.") Vita de Donna Olimpia Maidalchina (1666) is gossipy and untrustworthy; Capranica's Donna Olympia Pamfili (Milan, 1875, 3rd ed.) is fanciful and historically of no value. See also Ranke, Popes (Eng. trans., Austin), iii. 4o sqq. ; v. Reumont, Gesch. der Stadt Rom. iii. 2, p. 623 sqq. ; Brosch, Gesch. des. Kirchenstaates (188o) i. 409 sqq.; and the extended bibliography in Herzog-Hauck, Realencyklopadie, s.v. " Innocenz X." (T. F. C.)